Conductive charger with centering system

ABSTRACT

A device ( 1 ) for conductive charging, having a vehicle unit ( 2 ) that is fixedly mounted on a vehicle, and a stationary, but moveably mounted robot unit ( 3 ), wherein: the vehicle unit ( 2 ) can be operatively connected to the robot unit ( 3 ) in order to carry out the charging process; the two units ( 2, 3 ) each have a housing ( 4, 10 ) in which associated contact elements ( 5, 11 ) are disposed; in the robot unit ( 3 ), the contact elements ( 5 ) are recessed in the housing ( 4 ) of the robot unit ( 3 ); the contact elements ( 11 ) in the housing ( 10 ) of the vehicle unit ( 2 ) are fixed in place; and the vehicle unit ( 2 ) has a centering cone ( 24 ) and the robot unit ( 3 ) has a mating cone ( 25 ), or vice versa, as centering means which can be mutually operatively connected, characterised in that the tapering angles of the centering cone ( 24 ) and of the mating cone ( 25 ) are different.

The invention relates to an apparatus for conductive charging, in particular of electric vehicles at a base station, according to the features of the preamble of patent claim 1.

WO 2016/119001 A1 has already disclosed a plug connection for connecting in particular electrical lines for the purposes of conductive charging, comprising at least one female connecting element and one male connecting element, wherein the female connecting element receives the male connecting element in positively locking fashion and wherein the two connecting elements, in the case of positively locking contact, are releasably connectable in non-positively locking fashion, and wherein a connecting region of the male connecting element is designed to taper coaxially and comprises at least one displaceable contact body which, in a first position, is arranged within and, in a second position, is arranged so as to project out of, the male connecting element. With the apparatus described in this international patent application, conductive charging, in particular of electric vehicles, is possible at a base station. One connecting element is arranged on the autonomously driving vehicle, whereas the other connecting element is arranged in a fixed position but so as to be movable there within certain limits. If the vehicle moves with its connecting element in the direction of the static connecting element, these two connecting elements are placed in operative connection with one another in that, for electrical contacting, the respective contact bodies of the two connecting elements are placed in connection with one another such that the charging current can then flow.

In the case of this prior art, however, the contact elements (contact bodies) of the male connecting element are arranged movably in this male connecting element. In a first position, they are arranged entirely within the male connecting element, such that these contact bodies are protected against touching and contamination. Only when the two connecting elements have been brought together does the contact body, which was previously situated within the connecting element, move out of the male connecting element, such that these contact bodies can be placed in contact with the respective contact bodies of the female connecting element.

For the operation of the known apparatus, it is important that the two connecting elements abut against one another in a targeted and defined manner. For this purpose, a connecting region of the male connecting element is designed to taper coaxially, wherein the abutting region of the female connecting element is designed correspondingly. It is thus already possible that the two connecting elements to be placed in operative connection are guided in a targeted manner. However, practice has shown that this guidance is not sufficient owing to the rather shallow angle formed by the coaxial taper. In addition, it is disadvantageous that the coaxial tapers, that is to say the angles thereof in relation to the respective movement axis (taper angles), for example, are the same (of equal magnitude) both in the case of the male and in the case of the female connecting element. As a result, blockages can disadvantageously occur in particular during the start of the process of bringing these two connecting elements together, but sliding blockages can also disadvantageously occur during the further bringing-together of these two elements. In addition, the friction forces during the centering process are significantly increased, since the two centering means abut against one another over a large area.

The invention provides an improved apparatus for conductive charging. Conductive charging is to be understood to mean that the electrical contacts of a base station, at which charging energy is made available, are placed in operative connection with electrical contacts of an autonomously driving vehicle such that they touch one another for the purposes of charging. This conductive charging has the advantage over likewise known inductive charging, which takes place contactlessly, of significantly greater energy transmission, such that autonomous vehicles are much more quickly charged and ready for operation again.

For the apparatus for conductive charging as a whole, a vehicle part is provided which is arranged on the vehicle, in particular on the electric vehicle. Independently, and at an arbitrary other location, a robot part is provided that can be actuated by the vehicle for the purposes of charging. The robot part is therefore in a fixed position but is movable within certain limits at the location where charging is to take place. The purpose of this is that the vehicle with its vehicle part does not have to perform actuation whilst overlapping the robot part 100 percent, but rather the robot part locates the vehicle part when the vehicle has been parked for the purposes of charging.

Here, the apparatus comprises the vehicle part with a centering cone and the robot part with a counterpart cone as centering means that can be placed in operative connection with one another.

Based on this, it is provided according to the invention that the taper angles of the centering cone and of the counterpart cone are different. This advantageously minimizes the friction forces during the centering process and thus the placing of the robot part in operative connection with the vehicle part. In addition, sliding blockages during this centering process are avoided, such that operational reliability is thereby significantly increased and the contact elements of the two parts are placed in a defined position with respect to one another during the contacting. For this purpose, the centering cone, in particular the centering tip of the centering cone, is set down into the region of the counterpart cone. Here, a vertical centering force is set, that is to say imparted. Centering of the centering tip of the centering cone in the counterpart cone takes place, wherein, for this purpose, the surfaces of the centering tip of the centering cone slide on the surface of the counterpart cone This continues until the bearing surfaces of the mutually facing contact elements of vehicle part and robot part abut against one another. As a result of the different taper angles, fine centering occurs by way of the sliding of the mutually facing surfaces, in particular top sides, of the contact elements, until all surfaces are positioned relative to one another. As a result, a vertical insertion force, in particular a defined vertical insertion force, is advantageously imparted such that, if present, an engagement guard (see further below in the description) is pressed over (moved), with the protected contact elements on the side of the vehicle part being exposed (released). There is then a mutual overlap of the contact elements of the vehicle part and of the robot part, such that robust contacting is advantageously realized thereby.

Further advantageous configurations of centering cone and counterpart cone are specified in the subclaims. In this context, there are the following arrangement options:

First configuration: the centering cone is arranged on the vehicle part and the counterpart cone is arranged on the robot part.

Second configuration: the centering cone is arranged on the robot part and the counterpart cone is arranged on the vehicle part.

In a refinement of the invention, it is provided that the centering cone is of fully areal form. As a result, this centering means can be operated particularly robustly, in particular if the counterpart cone (see below) is of strut-like form. This also significantly minimizes the friction forces.

In a refinement of the invention, it is provided that the counterpart cone is of fully areal or strut-like form, in particular is formed by at least two cone struts. If both the centering cone and the counterpart cone are of fully areal form, the centering process can be carried out very effectively owing to the different taper angles, wherein, at the same time, the friction forces are significantly minimized because the centering cone and the counterpart cone, despite their fully areal configuration, abut fully in surface contact against one another only at the end of the centering process, not before.

In a refinement of the invention, it is provided that the taper angle of the centering cone is acute, preferably greater than 45°, more preferably greater than 60°, and the taper angle of the counterpart cone is shallow, preferably less than 10°, more preferably equal to 0°.

Preferably, the angles of the first section of the centering cone are acute, preferably greater than 45°, more preferably greater than 60°, and the angles of the respective second section of the centering cone and of the counterpart cone are shallow, preferably less than 10°, more preferably equal to 0°.

On the basis of these dimensional specifications, the centering process is particularly effective and can be carried out in a defined manner, and the friction forces are in turn significantly minimized. Furthermore, it is in particular the case with these dimensional specifications that pre-centering occurs before the contact elements of the vehicle part touch the contact elements of the robot part. Thus, owing to this pre-centering, the contact elements are already placed in a defined position relative to one another before the centering process, and the placing of the robot part in operative connection with the vehicle part, are performed and completed. Overall, this significantly improves the actual centering process as well as the contacting process and the respective operational reliability, in particular with regard to the longevity of the apparatus for charging.

The contact elements of the robot part are arranged in recessed fashion in a housing and thus so as to be protected against external touching or contamination, but are accessible to the contact elements of the vehicle part. The contact elements of the vehicle part must likewise be protected against touching or contamination. For this purpose, according to the invention, the contact elements of the vehicle part are covered by the engagement guard such that the contact elements of the vehicle part are not accessible for as long as no charging is being performed and for as long as the vehicle part has not been placed in operative connection with the robot part. Only when the robot part is moved in the direction of the vehicle part is this engagement guard moved relative to the housing of the vehicle part by the robot part such that the contact elements of the vehicle part, which are arranged in static fashion in the housing of the vehicle part, are exposed and can engage into corresponding free spaces in the robot part in order to touch and thus make contact with the contact elements, situated there, of the robot part. For this purpose, the engagement guard is supported on the housing of the vehicle part via springs. This configuration has the significant advantage that the engagement guard, as a mechanical component, is moved relative to the housing of the vehicle part, whereas the contact elements of the vehicle part are arranged in static fashion in said vehicle part, because, in practice, a movable mechanical component (without electrical function) can be much more effectively implemented than an electrically conductive component which, in the case of the prior art, not only serves for the electrical contacting but must simultaneously also be moved. As a result, the invention realizes a much simpler and more reliable construction of the apparatus for conductive charging. The contacts are likewise arranged in static fashion in the housing of the robot part. For example, the contacts in the robot part and in the vehicle part are overmolded with a plastics material in regions for the purposes of being fixed in the respective housing, wherein, after the overmolding process, a partial region of the contacts remains free for the purposes of the contacting or connection of supply lines.

An embodiment of the apparatus according to the invention and a method for operating this apparatus will be described below and discussed with reference to FIGS. 1 to 9.

FIG. 1 shows the basic construction of an apparatus 1 according to the invention for conductive charging. A vehicle part 2 is illustrated which has a housing in which contact elements (not illustrated here) and possibly further functional components are arranged. This vehicle part 2 is arranged at a suitable location, in particular on an underbody, of an electric vehicle, which preferably moves autonomously. Furthermore, a so-called robot part 3 is provided, which likewise has a housing in which has contact elements (likewise not illustrated here) and possibly also further functional components. These two parts 2, 3 are placed in operative connection in an approximately overlapping manner when the vehicle has arrived at a charging station at which the robot part 3 is present.

FIG. 1 shows that the robot part 3 is already in engagement with the vehicle part 2. Further means that are required for movement and position detection for the robot part 3 or the vehicle part 2 are present, but not illustrated.

FIG. 2 shows the side of the robot part 3 pointing in the direction of the vehicle part 2. It can be seen that the robot part 3 has a housing 4, preferably composed of plastic. Provided in this plastics housing 4 is a conductor ring 5 (multiple conductor rings 5 are illustrated), which conductor rings are connected to an energy source (not illustrated) for charging the vehicle. Each conductor ring 5 ends with a contact tab 6, which is provided, for example, for the purposes of contacting with a plug connector (not illustrated).

A conductor ring 5 is illustrated for example in FIG. 3. Such a conductor ring 5 is preferably implemented as a deep-drawn metal sheet which conducts the electrical current to the vehicle and which is arranged in a suitable position, and so as to be of a suitable size, in the housing 4 of the robot part 3. In this configuration, multiple conductor rings 5 are arranged concentrically one inside the other. Each conductor ring 5 has a base which is arranged at the encircling end of a cylinder section 8 and projects therefrom. Thus, the conductor ring 5 can be arranged, in particular fixed, in the housing 4 in a very effective manner. This applies in particular if a partial region of the cylinder section 8 together with the base 7 is surrounded by a plastics material which forms the housing 4. At least one recess 9 is provided over the circumference of the cylinder section 8. In this embodiment, exactly three recesses 9 are provided.

FIG. 4 shows the vehicle part 2, which is arranged with its underside (as viewed in FIG. 4) preferably on an underside of the vehicle (not illustrated). The vehicle part 2 also has a housing 10, preferably composed of plastic. Facing the top side (as viewed in FIG. 4) of the vehicle part 2 is a preferably plate-like engagement guard 12, which is arranged so as to be movable approximately plane-parallel with respect to the top side of the housing 10 of the vehicle part 2. The contacts 11 in the vehicle part 2, which are present but not yet fully visible here, are arranged in static fashion in the housing 10 of the vehicle part 2. For the corresponding contacts 11 in the vehicle part 2, cutouts are provided in the engagement guard 12, such that, when the engagement guard 12 is pressed together in the direction of the top of the vehicle part 2 by the robot part 3, the contacts 11 can pass through these cutouts and are thus exposed in order to be able to be applied to the contacts 5 in the robot part 3.

An exemplary configuration of the engagement guard 12 of areal form with the corresponding cutouts for the contacts 11 (spring contacts) is illustrated in FIG. 5. Such an engagement guard 12 may, like the housings 4, 10 of the two parts 2, 3, be produced for example in a plastics injection molding process. It is essential that the engagement guard 12 is movable relative to the vehicle part 2 in order to either protect or expose the contacts 11 in the housing 10 of the vehicle part 2, wherein the contacts 11 are arranged in static fashion in the housing 10 of the vehicle part 2.

It is furthermore evident and illustrated that the engagement guard 12 has a base 13 with a central opening 14. Provided around the central opening 14 is a region which runs obliquely with respect to the base 13 and in which multiple recesses 15 are arranged in encircling and also sloping fashion. The corresponding conductor springs 11 of the vehicle part 2 are passed through these recesses 15 and exposed when charging is to be performed, or are arranged under these recesses 15 when charging is not to be performed, such that the overall effect of the engagement guard 12 is that the conductor springs 11 are covered in the latter case. In addition, the engagement guard 12 also has, in encircling fashion, a plurality of recesses 16 through which further elements can be passed, for example in order to bring the vehicle part 2 and robot part 3 to one another in the correct position. In order to be able to install the engagement guard 12 in the correct position, it is furthermore possible for a coding lug 17 (or possibly further elements or also more than one coding lug) to be provided.

An exemplary configuration of a contact 11 (conductor spring) of the vehicle part 2 is illustrated in FIG. 6. This contact 11, illustrated by way of example, is in turn a deep-drawn metal sheet, which likewise conducts the electrical current to the vehicle. As the base 18, an outer ring can be seen, from which projecting outwards, a contact tab (in turn for the connection of a plug connector (not illustrated)) and contacts 20 angled toward the inside extend upward, wherein these contacts 20 are either exposed or covered, for the purposes of protection against touching or contamination, by the engagement guard 12. If a plurality of such conductor springs 11 are arranged concentrically in the robot part or, in this case, the vehicle part 2, these vary in terms of their diameters.

Finally, FIG. 7[A-C] shows the method for operating the two parts 2, 3 as described above and as shown in FIGS. 1 to 6.

In the illustration on the left in FIG. 7[A], it can be seen that, although the vehicle part 2 has already been brought into the region of the robot part 3, no contacting has yet been performed. This means that the robot part 3 first has to locate and set its exact position in relation to the vehicle part 2, for which purpose corresponding sensors and means for moving the robot part 3 are provided, but not illustrated.

The required overlap of the robot part 3 with the vehicle part 2 is illustrated, after having been achieved, in the middle illustration of FIG. 7[B]. It can be seen here that the contact elements 11 in the vehicle part are still arranged within the housing 10 of the vehicle part 2 and are covered by the engagement guard 12. The engagement guard 12 is pressed in the direction of the housing 10 by the robot part 3 counter to the spring force, such that the contacts 11 in the vehicle part 2 are thus exposed by the engagement guard 12 in order that they can abut against the contacts 5 of the robot part 3. This operative connecting and thus contacting of the contacts 5, 11 of the two parts can be seen in the right-hand illustration of FIG. 7[C], such that the charging process can now take place.

In order that the vehicle part 2 and the robot part 3 can be brought together in a defined position relative to one another, the housing 4 of the robot part 3 has a dome 21 which is passed through the central opening 14 of the engagement guard 12. Here, the dome 21 of the robot part 3 is guided by a corresponding counterpart element on the vehicle part 2, which is designed and suitable for entering into connection with the dome 21 and in so doing guiding the robot part 3 during the movement toward the vehicle part 2.

In the middle illustration of FIG. 7[B], it is also illustrated for the sake of clarity that the engagement guard 12 can be moved in a movement direction 22 from its initial position 23 and vice versa. The initial position 23 of the engagement guard 12 is a position in which the engagement guard 12 is arranged spaced apart from, and plane-parallel with respect to, a defined reference point (or reference surface) of the housing 10 of the vehicle part 2. The spacing in this initial position 23 between the engagement guard 12 and the housing 10 of the vehicle part 2 is defined and is implemented for example by means of a spring arranged between the engagement guard 12 and the housing 10 of the vehicle part 2, preferably multiple springs, in turn preferably at each corner of the preferably square engagement guard 12. This at least one spring is compressed in the movement direction 22 and the engagement guard 12 is moved in the direction of the defined point on the housing 10 of the vehicle part 2 when a defined point (or a defined surface) of the housing 4 of the robot part 3 moves toward the vehicle part 2. With further movement of the robot part 3 in the movement direction 22 toward the vehicle part 2, the engagement guard 12 is also moved further in the direction of the housing 10 of the vehicle part 2, and in the process the at least one spring is compressed such that the contacts 11 of the vehicle part 2 are exposed and can be placed in operative connection with the contacts 5 of the robot part 3. As already stated, this position of vehicle part 2 and robot part 3 relative to one another is illustrated in the lower right-hand illustration of FIG. 7[C].

It is self-evident that, after completion of the charging process, the two parts 2, 3 are separated from one another again in the reverse procedure, wherein the contacts 11 which are static in the housing 10 of the vehicle part 2 are again covered by the engagement guard 12 after the robot part 3 has been removed from the vehicle part 2.

In FIGS. 8 and 9, the centering means of the vehicle part 2 and of the robot part 3 are once again explicitly illustrated.

In this embodiment, according to FIG. 8, a centering cone 24 is provided within the housing 10 of the vehicle part 2. This centering cone 24 proceeds with its larger diameter from a base of the housing 10 and projects from this base. It tapers sharply upward to a point or is (as illustrated) flattened at its tapering end. The centering cone 24 is preferably produced together with the housing 10, though it may also be produced as a separate component and then arranged on the housing 10. As can be seen in FIG. 8, the centering cone 24 is advantageously arranged centrally and coaxially within the contact elements 5, which are arranged coaxially to one another, of the vehicle part 2.

A counterpart cone 25 of the robot part 3 is illustrated in FIG. 9. This counterpart cone 25 may also (as illustrated) be a constituent part of the housing 4. It may however also be a separate component which is arranged on the housing 4. The counterpart cone 25 is also arranged centrally and coaxially within the contact elements 11 of the robot part 3. In the embodiment according to FIG. 9, the counterpart cone 25 is formed by cone struts 26 (two cone struts 26 are visible, but there are in fact four or more than four, but possibly also fewer than four, cone struts 26). However, like the centering cone 24, the counterpart cone 25 may also be of fully areal form.

In the embodiment illustrated in the figures, it can be seen that the centering cone 24 which tapers to a point is arranged on the vehicle part 2 and the counterpart cone 25 is arranged on the robot part 3. It applies both to this specific embodiment and in general that the illustrated and correspondingly described cones may also be arranged in reversed fashion on the respective part 2, 3. This applies in particular to the case in which the centering cone 24 designed as a centering tip is arranged on the robot part 3 and the correspondingly configured counterpart cone 25 is arranged on the vehicle part 2 (that is to say in the reverse of the situation illustrated for example in FIGS. 8 and 9), because, owing to the flat nature of the counterpart cone 25 on the vehicle part 2, this part can be of particularly flat configuration, because the installation space under the vehicle is often very restricted. Since there is more space available in the region of the robot part 3, the centering cone 24 that is equipped with an acute taper angle can be better arranged there.

LIST OF REFERENCE

-   1 Apparatus for charging -   2 Vehicle part -   3 Robot part -   4 Housing -   5 Conductor ring (=contact or contact element) -   6 Contact tab -   7 Base -   8 Cylinder section -   9 Recess -   10 Housing -   11 Conductor springs (=contact or contact element) -   12 Engagement guard -   13 Base -   14 Central opening -   15 Recess -   16 Cutout -   17 Coding lug -   18 Base -   19 Contact tab -   20 Contact springs -   21 Dome -   22 Movement direction -   23 Initial position -   24 Centering cone -   25 Counterpart cone -   26 Cone strut 

1. An apparatus for conductive charging, the apparatus comprising: a vehicle part fixed on a vehicle; a movable robot part, the vehicle part being movable into operative connection with the robot part for the purposes of charging, the parts each having a respective housing holding a respective set of contacts, the contacts in the robot part being recessed fashion in the housing of the robot part and the contacts being fixed in the housing of the vehicle part; a centering cone in the vehicle part; and a counterpart cone in the robot part, or vice versa, forming centering means which can be placed in operative connection with one another, taper angles of the centering cone and of the counterpart cone being different.
 2. The apparatus for conductive charging as claimed in claim 1, wherein the centering cone and the counterpart cone each have an inner section and an outer section, an apex angle of the inner section of the centering cone of the robot part being greater than an apex angle of the outer section.
 3. The apparatus for conductive charging as claimed in claim 2, wherein the inner section of the counterpart cone of the vehicle part or of the robot part has a passage opening.
 4. The apparatus for conductive charging as claimed in claim 3, wherein the passage opening has a centering bevel or a rounding at its inner side.
 5. The apparatus for conductive charging as claimed in claim 2, wherein the inner section of the counterpart cone of the vehicle part has a counterpart shape fittable with the inner section of the centering cone of the robot part, or vice versa.
 6. The apparatus for conductive charging as claimed in claim 2, wherein the inner section of the centering cone is of fully areal form.
 7. The apparatus for conductive charging as claimed in claim 2, wherein the outer section of counterpart cone is of fully areal or strut-like form, or is formed by at least two cone struts.
 8. The apparatus for conductive charging as claimed in claim 2, wherein the angles of the first section of the centering cone are acute and greater than 45°, and the angles of the respective second section of the centering cone and of the counterpart cone are shallow, preferably less than 10°.
 9. The apparatus for conductive charging as claimed in claim 1, further comprising, on the vehicle part, an engagement guard movable relative to the housing of the vehicle part and by means of which the contacts of the vehicle part are protected or exposed.
 10. The apparatus for conductive charging as claimed in claim 9, wherein the contact elements err of the robot part are recessed in the housing so as to be protected against external touching or contamination, but are accessible to the contact elements of the vehicle part.
 11. The apparatus for conductive charging as claimed in claim 9, wherein the engagement guard is supported on the housing of the vehicle part via springs.
 12. The apparatus for conductive charging as claimed in claim 9, wherein the contact elements of the vehicle part are covered by the engagement guard such that the contact elements of the vehicle part are not accessible for as long as no charging is being performed and for as long as the vehicle part has not been placed in operative connection with the robot part, and only when the robot part is moved in the direction of the vehicle part is this engagement guard moved relative to the housing of the vehicle part by the robot part such that the contact elements of the vehicle part, which are arranged in static fashion in the housing of the vehicle part, are exposed and can engage into corresponding free spaces in the robot part in order to touch and thus make contact with the contact elements, situated there, of the robot part.
 13. The apparatus for conductive charging as claimed in any of the preceding claims, claim 1, wherein the contacts in the robot part and/or the contacts of the vehicle part are overmolded with a plastics material in regions for the purposes of being fixed in the respective housing of the robot part and/or of the vehicle part. 